Smoking exacts a particularly high toll. Nearly 80% of the 6.3m deaths from smoking in 2010 occurred in middle- and low-income countries, says the Risking Your Health report.

Smoking is decreasing in richer countries but increasing in parts of the developing world. The Bank says low- and middle-income countries are in the grip of a tobacco epidemic, characterised by a sharp rise in smoking, particularly among men, after it peaked in rich countries in the 1960s and 70s.

In China, where smoking accounts for 1.2m deaths a year, it is the number one killer. In 2009, the country consumed more than 38% of the world's cigarettes, followed by Russia, the US, Indonesia and Japan.

The report finds that tobacco-related illnesses place a considerable financial burden on countries. The bank cites a study in Bangladesh that found families with at least one member afflicted by a tobacco-related illness, such as heart disease, lung cancer and oral cancer, spent 5.1% of their household monthly expenditure on tobacco and 10.2% on treating their illnesses.

In Vietnam, even after accounting for government subsidies, the out-of-pocket expenses for each hospital admission of lung cancer, chronic obstructive pulmonary disease and heart disease amounted to $285, or about 34%, of per capita gross domestic product.

In an area of Tanzania, health spending triggered by HIV and Aids was more than 70% greater than for other diseases over a two-year period. Together with funeral costs, this amounted to more than the annual household income.

"Individuals' risky behaviours that cluster among the poor ripple throughout entire populations, crippling families' potential and undermining the great health and economic progress we've seen in low- and middle-income countries in recent years," said Tim Evans, director of health, nutrition and population at the World Bank.